Morphology And Properties Of Nanocrystalline Nickel Layer Of Ultrasonic Power Study

In this paper, the technology and performance of nanonickel coatings and nickel-nanoalumina composition coatings on copper substrates by ultrasonic electrodeposition were studied. By means of XRD, SEM, IM6 workstation and microhardmeter ect., the morphology, structure and performance of coatings were analyzed. And the influence law of ultrasonic in electrodeposition process was preliminarily discussed.1, The research results of ultrasonic electrodeposition rates in different process conditions show: with the power of ultrasonic increasing at 35kHz, the pluse electrodeposition rate of nickel decreased;with the power of ultrasonic increasing at 130kHz, the pluse electrodeposition rate of nickel went up first and then descended;with the power of ultrasonic increasing at 35 and 130kHz, the DC electrodeposition rate of nickel coatings went up first and then descended.2, The analysis results of structures of nickel coatings and nickel-nanoalumina composite coatings electrodeposited in different process conditions show: their structures were compact, homogeneous and flat;the addition of saccharin could reduce the preferred orientation of nickel coatings crystal plane(200);ultrasonic could change the preferred orientation of various nickel coatings crystal planes, yet which was not apparent;nickel coatings transformed from non-preferred orientation to preferred orientation as the increasing of electrodeposition time;ultrasonic could refine the crystal grain, the minimal average grain size of nickel coatings was 15.4 nm.3, The test results of microhardness of nickel coatings and nickel-nanoalumina composite coatings show: with the power of ultrasonic increasing, the microhardness of nickel coatings and nickel-nanoalumina composite coatings enhanced by 172HV_0.1 and 160HV_0.1 respectively than those untreated by ultrasonic;with the current density and time increasing, the microhardness of nickel-nanoalumina composite coatingsenhanced with the maximal value 564HVo.i and 651HVo.i respectively.4^ The test results of porosities of nickel coatings and nickel-nanoalumina composite show that the porosity of coatings electrodeposited by ultrasonic at 130kHz were bigger than that of coatings electrodeposited by ultrasonic at 35kHz but both of which were less than that of coatings electrodeposited without ultrasonic.5^ The teat results of cohesions of coatings to substrates show that the cohesion of nickel coatings and Ni-nanoalumina composite coatings were very good.6> The teat results of corrosion resistances of electrodeposition coatings in different process conditions show: the corrosion resistances of pure nickel coatings with the average grain size of 21.71nm were better than those pure nickel coatings with the average grain size of 80.04nm;the corrosion resistances of nickel-nanoalumina composite coatings DC electrodeposited by ultrasonic enhanced as the increasing of the average grain size.